Armature of rotary electric machine and manufacturing method thereof

ABSTRACT

In a rotary electric machine, coils to be wound around an armature are wound so as to have a good magnetic balance. In a rotary electric machine formed with four poles, ten slots, and twenty commentator segments, a pair of coils that respectively conduct an electric current to the commutator segments adjoining an arbitrary commutator segment at both sides in the circumferential direction are caused to face permanent magnets, that are adjoining poles, to be poles opposite from each other, and one coil is wound in a normal winding state, and the other coil, in a reverse winding state.

This application is the U.S. National Stage of PCT/JP 2004/015181, filedOct. 7, 2004, which claims priority from JP 2003-349742, filed Oct. 8,2003, the entire disclosures of which are incorporated herein in theentireties by reference thereto.

BACKGROUND

The disclosure relates to the technical field of an armature of a rotaryelectric machine that is mounted on, for example, a vehicle and amanufacturing method thereof.

Generally, as this type of rotary electric machine, known is an electricmotor. The electric motor has a yoke where magnetic poles are formed bya plurality of pairs of permanent magnets provided on the innercircumferential surface and an armature. A plurality of slots are formedin the armature extending in an axial direction around thecircumferential direction on the outer periphery of a core. A pluralityof coils, each coil formed by winding wire wound in the slots with apredetermined interval, conduct an electric current to adjoiningcommutator segments. When a high torque, as well as a reduction in size,are demanded in such an electric motor, the demand has been satisfied byproviding the electric motor with multiple poles by using a plurality ofpairs of permanent magnets and increasing the number of commutatorsegments and slots. However, in such an electric motor, it has beenknown that, when the commutator segments around which and to which coilends are hung and connected and coil winding positions are lap-wound ina state where these are almost opposed in the axial direction, magneticimbalance occurs to cause whirling based on a torque ripple and thelike.

As a remedy therefore, it has been promoted to form coils by winding awinding wire that conducts an electric current to arbitrary commutatorsegments around the preset arbitrary slots and the slots facing thearbitrary slots in the radial direction in a state of series connectionand to thereby improve magnetic balance (see Japanese PublishedUnexamined Patent Application No. 2002-305861).

SUMMARY

However, the conventional art described above is carried out in anarmature having slots and commutator segments provided in the samenumber, and there is no suggestion of the case of a structure whereslots are provided with half as many as segments, which is a problem tobe solved by the invention.

In consideration of the foregoing circumstances, the invention has beenmade to, at least, solve the identified problems. As disclosed, a rotaryelectric machine including an armature on which a plurality of coils,each coil formed by a winding wire wound around the slots with apredetermined number of slots therebetween out of a plurality of slotsprovided side by side in a circumferential direction, conduct anelectric current to adjoining commutator segments and a yoke providedwith magnetic poles. The slots are provided with half the number ofcommutator segments, and the coils are formed as a pair of coilsrespectively that conduct an electric current to commutator segmentsadjoining at both sides in the circumferential direction with referenceto an arbitrary commutator segment, the pair of coils face oppositepoles positioned differently from each other, and one coil is wound in anormal winding state, and the other coil, in a reverse winding state.With this structure, magnetic balance of the armature can be improved.

In one case, the rotary electric machine is formed with N magneticpoles, n pieces of slots, and 2n pieces of commutator segments, a pairof coils that respectively conduct an electric current to threecommutator segments adjoining at both sides in the circumferentialdirection with reference to an arbitrary commutator segment having anangle of approximately (360/N), and one thereof is wound as a normalwinding coil, and the other, as a reverse winding coil. With thisstructure, magnetic balance of the armature can be improved.

In another case, the rotary electric machine is formed with N magneticpoles, n pieces of slots, and 2n pieces of commutator segments in whicha number (2n/N) obtained by dividing the number of commutator segmentsby the number of magnetic poles is a natural number, and ((2n/N)−1)coils formed in a manner respectively conducting an electric current to(2n/N) pieces of arbitrary commutator segments adjoining in thecircumferential direction are wound so as to respectively have an angleof approximately {(1+2m)×(360/N)} where m is a natural number including0 and the coils are wound so that a normal winding alternates with areverse winding. With this structure, magnetic balance of the armaturecan further be improved.

The coils are wound with one slot therebetween, and with this structure,a reduction in size and weight, a reduction in cost, and high efficiencycan be realized.

Further, the rotary electric machine including an armature on which aplurality of coils, each coil formed by a winding wire wound around theslots with a predetermined number of slots therebetween out of aplurality of slots provided side by side in a circumferential direction,conduct an electric current to adjoining commutator segments and a yokeprovided with magnetic poles, the slots are provided in half the numberof commutator segments, the coils are formed as pairs of coils thatrespectively conduct an electric current to commutator segmentsadjoining at both sides in the circumferential direction with referenceto an arbitrary commutator segment, each pair of coils face the samepoles positioned different from each other, and the respective coils arewound in the same winding direction. With this structure, magneticbalance of the armature can be improved.

The rotary electric machine is formed with N magnetic poles, n pieces ofslots, and 2n pieces of commutator segments, a pair of coils thatrespectively conduct an electric current to three commutator segmentsadjoining at both sides in the circumferential direction with referenceto an arbitrary commutator segment have an angle of approximately(360×2/N), respective coils are wound in the same winding direction.With this structure, magnetic balance of the armature can be improved.

The coils are wound with one slot therebetween, and with this structure,a reduction in size and weight and a reduction in cost can be realized.

In the armature, two layers of coils are wound in a radial direction,and with reference to an arbitrary slot, a pair of first coils in theradial direction to be wound with the arbitrary slot therebetween and apair of second coils in the radial direction to be wound with a slotadjoining the arbitrary slot therebetween are wound at a winding amountbased on a preset ratio. With this structure, commutation is improved sothat durability of the brushes can be enhanced.

In the first and second coils, each pair of coils are wound with apositional displacement from each other in the radial direction, andwith this structure, not only is commutation improved so that durabilityof the brushes can be enhanced, but also a space factor is improved sothat a reduction in size and weight can be realized.

Further, adjoining slots are formed so that a groove width of one slotis narrow at an inner radial side and wide at an outer radial side and agroove width of the other slot is wide at an inner radial side andnarrow at an outer radial side. With this structure, the space factorcan be further improved so that a reduction in size and weight can berealized.

Further, in a method for producing an armature of a rotary electricmachine, a plurality of coils, each coil is formed on the armature by awinding wire wound around the slots with a predetermined number of slotstherebetween out of a plurality of slots provided side by side in acircumferential direction, conduct an electric current to adjoiningcommutator segments. A yoke is provided with magnetic poles, in whichthe slots are provided with half the number of commutator segments, andthe coils are wound, while arranging a pair of coils that respectivelyconduct an electric current to commutator segments adjoining at bothsides in the circumferential direction with reference to an arbitrarycommutator segment so as to cause the same to face opposite polespositioned different from each other, so that one coil results in anormal winding, and the other coil, a reverse winding. With thisstructure, magnetic balance of the armature can be improved.

In one method, the rotary electric machine is formed with N magneticpoles, n pieces of slots, and 2n pieces of commutator segments, a pairof coils that respectively conduct an electric current to threecommutator segments adjoining at both sides in the circumferentialdirection with reference to an arbitrary commutator segment have anangle of approximately (360/N), and one thereof is wound as a normalwinding coil, and the other, as a reverse winding coil. With thisstructure, magnetic balance of the armature can be improved.

In another method, the rotary electric machine is formed with N magneticpoles, n pieces of slots, and 2n pieces of commutator segments in whicha number (2n/N) obtained by dividing the number of commutator segmentsby the number of magnetic poles is a natural number, and ((2n/N)−1)coils formed in a manner respectively conducting an electric current toarbitrary (2n/N) commutator segments adjoining in the circumferentialdirection are wound so as to respectively have an angle of approximately{(1+2m)×(360/N)} where m is a natural number including 0 and so that anormal winding alternates with a reverse winding. With this structure,magnetic balance of the armature can further be improved.

Further, the coils are wound with one slot therebetween. With thisstructure, a reduction in size and weight and a reduction in cost can berealized.

In another method for producing an armature, of a rotary electricmachine, on which a plurality of coils, each coil formed by making awinding wire wound around the slots with a predetermined number of slotstherebetween out of a plurality of slots provided side by side in acircumferential direction, conduct an electric current to adjoiningcommutator segments and a yoke provided with magnetic poles. The slotsare provided with half the number of commutator segments, and the coilsare provided, while arranging a pair of coils that respectively conductan electric current to commutator segments adjoining at both sides inthe circumferential direction with reference to an arbitrary commutatorsegment so as to cause the same to face the same poles positioneddifferent from each other, so that the respective coils are wound in thesame winding direction. With this structure, magnetic balance of thearmature can be improved.

In this method, the rotary electric machine is formed with N magneticpoles, n pieces of slots, and 2n pieces of commutator segments, a pairof coils, that respectively conduct an electric current to threecommutator segments adjoining at both sides in the circumferentialdirection with reference to an arbitrary commutator segment, has anangle of approximately (360×2/N), and the respective coils are wound inthe same winding direction. With this structure, magnetic balance of thearmature can further be improved.

Thus, the coils are wound with one slot therebetween, and, with thisstructure, a reduction in size and weight and a reduction in cost can berealized.

In the armature, two layers of coils are wound in a radial direction,and with reference to an arbitrary slot, a pair of first coils in theradial direction are wound with the arbitrary slot therebetween and apair of second coils in the radial direction are wound around thearbitrary slot and adjoining the first coils in the circumferentialdirection are wound at a winding amount based on a preset ratio. Withthis structure, commutation is improved so that durability of thebrushes can be enhanced.

In the first and second coils, each pair of coils are wound with apositional displacement from each other in the radial direction. Withthis structure, not only is commutation improved so that durability ofthe brushes can be enhanced, but also the space factor is improved sothat a reduction in size and weight can be realized.

Adjoining slots are formed so that a groove width of one slot is narrowat an inner radial side and wide at an outer radial side and a groovewidth of the other slot is wide at an inner radial side and narrow at anouter radial side. With this structure, the space factor can further beimproved so that a reduction in size and weight can be realized.

In the disclosed apparatus and method, whirling is reduced, wherebyvibration and noise can be reduced, and a high-performance rotaryelectric machine can be provided.

Also a reduction in size and weight, a reduction in cost, and highefficiency can be realized.

Additionally, commutation is improved so that durability of the brushescan be enhanced.

Further, the space factor is improved so that a reduction in size andweight can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be made with reference to the drawings, in which:

FIG. 1 is a cross-sectional, partially-cutaway side view of an electricmotor;

FIG. 2 is a pattern view where an armature has been developed;

FIG. 3 is a cross-sectional view of an armature;

FIG. 4 is a development pattern explanatory view for a positionalrelationship between the coils and commutator segments;

FIG. 5 is a cross-sectional view for a positional relationship betweenthe slots and coils;

FIG. 6 is a development pattern explanatory view for a positionalrelationship between the coils and commutator segments according to asecond embodiment;

FIG. 7 is a cross-sectional view of an armature according to the secondembodiment;

FIGS. 8(A) and (B) are a cross-sectional view of an armature in a statewhere one of the winding wires has been wound and a cross-sectional viewof an armature in a state where both wiring wires have been wound in thesecond embodiment, respectively;

FIG. 9 is a development pattern explanatory view for a positionalrelationship between the coils and commutator segments according to athird embodiment;

FIGS. 10(A) and (B) are a cross-sectional view of an armature in a statewhere one of the winding wires has been wound and a cross-sectional viewof an armature in a state where both wiring wires have been woundaccording to a fourth embodiment, respectively;

FIG. 11 is a development pattern explanatory view for a positionalrelationship between the coils and commutator segments according to thefourth embodiment;

FIG. 12 is a development pattern explanatory view for a positionalrelationship between the coils and commutator segments according to afifth embodiment;

FIG. 13 is a cross-sectional view of an armature showing a wound stateof coils according to a sixth embodiment;

FIG. 14 is a cross-sectional view of an armature showing a wound stateof coils according to a seventh embodiment;

FIG. 15 is a cross-sectional view of an armature showing a wound stateof coils according to an eighth embodiment;

FIGS. 16(A) and (B) are a front view of a commutator and across-sectional view along 16-16 of FIG. 16(A) according to the eighthembodiment, respectively.

FIGS. 17(A), (B), and (C) are a pattern cross-sectional view of anarmature for explaining a wound state of coils, a front view of aninsulator, and a cross-sectional view along 17-17 of FIG. 17(B)according to a ninth embodiment, respectively.

DETAILED DESCRIPTION OF EMBODIMENTS

Next, a first exemplary embodiment will be described with reference toFIGS. 1 to 5. In the drawings, reference numeral 1 designates anelectric motor (rotary electric machine) used as a driving source ofelectric equipment mounted on a vehicle. To the inner circumferentialsurface of a yoke (motor housing) 2, that is a component of the electricmotor 1 and is formed in a cylindrical form with a bottom, permanentmagnets 3 are fixed so that two pairs of N and S poles are formed in acircumferential direction, whereby the electric motor is formed as aquadrupole electric motor 1. Reference numeral 4 designates an armature.To a shaft (armature shaft) 5 that is a component of the armature 4, acore 6, formed by laminating a plurality of ring-shaped plates 6 a, isexternally fitted in an integrated manner. A commutator 7, positioned ata front end of the core 6, is externally fitted and fixed to the shaft5. The shaft 5 of the armature 4 is rotatably supported at its base endby the yoke 2 via a bearing 2 a, and is internally provided so as to befreely rotatable in the yoke 2. Also, a cover 2 b is provided at an openend of the yoke 2, and a holder stay 8 is integrally provided on thecover 2 b. Brush holders 8 a positioned at four circumferential pointsare formed in the holder stay 8. Brushes 8 b are internally provided inthe brush holders 8 a so as to be freely protruded and depressed. As aresult, the protruding ends of the brushes 8 b abut (contact) thecommutator 7. An external electric supply is supplied to the commutator7 via the brushes 8 b. These basic structures are formed according to aconventional technique.

Formed on the outer periphery of the ring-shaped plates 6 a forming thecore 6, are ten teeth 6 b. Each tooth 6 b is shaped like the capitalletter T. By externally fitting a plurality of plates out of theseplates 6 a onto the shaft 5 like a whirl-stop, ten dovetailgroove-shaped slots 6 c are provided in a concave manner between theadjoining teeth 6 b to extend in the axial and the circumferentialdirections on the outer periphery of the core 6.

On the other hand, the commutator 7 is constructed by disposing aplurality of commutator segments 7 b, formed of conductive long platesparallel in the axial direction and arranged in the circumferentialdirection in a mutually isolated state on the outer circumferentialsurface of a ring-shaped member 7 a externally fitted onto the shaft 5.Here, twenty commutator segments 7 b, twice the number of the slots 6 c,are provided, whereby the electric motor 1 is formed as an electricmotor with four polesten slots 6 c, and twenty commutator segments 7 b.Also, at an end of each commutator segment 7 b, facing the core 6 side,a riser 7 c curved by folding back the same to the radially outer sideis formed in an integrated manner.

By winding enamel-coated winding wires 9 between the slots 6 cpositioned at arbitrary points of the core 6 and provided with apredetermined interval according to a winding process described later,twenty coils 10 are wound around the outer periphery of the core 6. Thewinding wires 9 to be winding-start ends and winding-finish ends of therespective coils 10 have been passed around, that is, engaged with, therisers 7 c of the respective corresponding commutator segments 7 b, andthe passed-around winding wires 9 to be winding-start ends andwinding-finish ends have been set so that the commutator segments 7 band coils 10 corresponding thereto are electrically connected (areconductive) by fusing with the commutator segments 7 b at the riser 7 csections (hung-around sections).

Next, a process for winding the coils 10 will be described withreference to FIGS. 2 to 5. Here, in a conventional electric motor inwhich the twenty commutator segments 7 b of the armature 4, with half asmany slots 6 c as the commutator segments 7 b being provided, when lapwinding, that is normally generally used for the armature 4, isexecuted, the winding wire is wound between two slots with one slottherebetween. The pair of coils formed in such a manner respectivelyconducting an electric current to commutator segments adjoining at bothside portions with reference to an arbitrary commutator segment are inthe same state in terms of the winding direction. In contrast thereto,according to the invention, a pair of coils 10 formed so as torespectively conduct an electric current to commutator segments 7 badjoining at both side portions with reference to an arbitrarycommutator segment 7 b have been set so that one thereof is wound in anormal winding state, and the other, in a reverse winding state, interms of the winding direction.

Also, FIG. 2 is a drawing in which the armature 4 has been linearlyportrayed for explaining a relationship among the commentator segments 7b, slots 6 c, and coils 10. The gaps with respect to the adjoining teeth6 b are equivalent to the slots 6 c. Moreover, FIG. 3 is across-sectional view for explaining a process for winding the windingwires 9 around the armature 4, and winding directions of the windingwires 9 in cross-sections of the coils 10 formed as such are shown bymarks ● and x. Furthermore, FIG. 4 is a pattern explanatory view, inwhich positions of the slots 6 c that the winding wires 9 stride overare denoted by symbols in the coil 10, for explaining a positionalrelationship between the coil 10 positions and commutator segments 7 b(risers 7 c) that conduct an electric current to the coils 10. FIG. 5 isa cross-sectional view for explaining a positional relationship of thewound coils 10.

In these drawings, a description will be given with reference numerals 1to 20 used for the respective risers 7 c, reference numerals I to X usedfor the respective slots 6 c, and reference numerals (i-1), (i-2),(ii-1), (ii-2), (iii-1), . . . , (x-1), and (x-2) used for the twentywound coils wound, respectively.

Namely, the coils 10 to be wound around the armature 4 according to theembodiment are structured so that the winding wire 9 is wound betweenthe slots 6 c around teeth 6 b, with one slot 6 c therebetween. Forexample, when winding of one end of the winding wire 9 has started whileconducting an electric current to the first riser, the winding wire 9passed around the first riser 7 c is wound into the Xth and IInd slots 6c with the Ist slot 6 c therebetween a plurality of times (in theembodiment, twenty times), and by passing the same around the secondriser 7 c, an (i-1)th coil is formed. In this case, the (i-1)th coil 10is in a winding direction (regarded as a normal winding state) where thewinding wire 9 is passed around so as to reach from the Xth slot 6 cside to the IInd slot 6 c. Thereafter, by winding the winding wire 9passed around the second riser 7 c a plurality of times (in the presentembodiment, twenty times) at a section with an angle of approximately 90degrees in the circumferential direction with respect to the (i-1)thcoil 10, namely around the IIIrd and the Vth slots 6 c with the IVthslot 6 c therebetween, and by passing the winding wire 9 around thethird riser 7 c, an (i-2)th coil 10 is formed. At this time, the (i-2)thcoil 10 is wound so as to be in an opposite winding direction (referredto as a reverse winding state) from the (i-1)th coil 10 as a result thatthe winding wire 9 is passed around so as to reach from the Vth slot 6 cside to the IIIrd slot 6 c, whereby the (i-1)th coil 10 and (i-2)th coil10 are set so that, when one faces the N-pole permanent magnet 3 of theyoke 2, the other faces the S pole, and when a power is supplied tothese coils 10, an excitation corresponding to the respective polesoccurs.

Subsequently, although the (ii-1)th coil 10 is formed by winding thewinding wire 9 passed around the third riser 7 c between the Ist toIIIrd with the IInd slot 6 c therebetween and passing the same aroundthe fourth riser 7 c, the (ii-1) coil 10 is wound in a normal windingstate as a result the winding wire 9 is passed around so as to reachfrom the Ist slot 6 c side to the IIIrd slot 6 c. Furthermore, bywinding the winding wire 9 passed around the fourth riser 7 c at asection with an angle of approximately 90 degrees in the circumferentialdirection with respect to the (ii-1)th coil 10, namely around the IVthand VIth slots 6 c with the Vth slot 6 c therebetween and passing thesame around the fifth riser 7 c, a (ii-2)th coil 10 is formed. At thistime, the (ii-2)th coil 10 is wound in a reverse winding state oppositefrom the (ii-1)th coil 10 as a result that the winding wire 9 is passedaround so as to reach from the VIth slot 6 c side to the IVth slot 6 c.

As such, the winding wire 9 is set so as to be wound around the slots 6c in a manner sequentially passed around the sixth, seventh, and eighthrisers 7 c . . . based on the winding states, and in this case, asmentioned above, to the commutator segments 7 b adjoining at both sidesin the circumferential direction with reference to an arbitrarycommutator segment 7 b (riser 7 c), a pair of coils 10 has beenrespectively connected so as to conduct an electric current, and thepair of coils 10 have been set so as to be wound in a positionalrelationship provided with a circumferential angle of approximately 90degrees so as to be caused, in the yoke 2 constructed with four poles,to face the poles opposite from each other, and so that one ((i-1) to(x-1)th) of the coils 10 is wound in a normal winding state and theother ((i-2) to (x-2)th) of the coils 10 is wound in a reverse windingstate.

Thereby, as shown in FIG. 5, around the slots 6 c at an arbitrary pointwith one slot 6 c therebetween, a pair of coils 10 are to berespectively wound, and in this case, it has been set so that a pair ofcoils 10 in a normal winding state and a reverse winding state are woundaround the slots 6 c.

Therein, when a power is supplied to the coils as a result of thebrushes 8 slidable contact with the commutator 7, the (i-1)th coil 10and (i-2)th coil 10 formed in a manner to respectively conduct anelectric current to the first riser 7 c and third riser 7 c adjoining atboth sides in the circumferential direction with reference to the secondriser 7 c (commutator segment 7 b), for example, are wound with an angleof approximately 90 degrees in the circumferential direction so as toface the poles opposite from each other. The (i-1)th coil 10 is wound ina normal winding state, and the (i-2)th coil 10, in a reverse windingstate, whereby a pair of coils 10 of the (i-1)th coil 10 and a(viii-2)th coil 10 are wound around the slots 6 c with the Ist slot 6 ctherebetween. As a result, the coils 10 connected between the brushes 8of opposite poles are faced between the adjoining N and S poles tobalance magnetism therebetween, thus improving magnetic balance allround the outer periphery of the armature 4.

In the embodiment structured as described, as mentioned above, the yoke2 is constructed with four poles. On the other hand, when the windingwire 9 is wound around the armature 4, there are twenty commutatorsegments 7 b provided on the armature 4, ten slots 6 c are formed on theouter periphery of the core 6 c, and a pair of coils 10 thatrespectively conduct an electric current to the commutator segments 7 badjoining at both sides in the circumferential direction with referenceto an arbitrary commutator segment 7 b are caused to face the polesopposite from each other. One coil 10 of the pair is wound as a normalwinding coil 10, and the other, as a reverse winding coil 10. Thereby,the coils 10 connected between the brushes 8 of opposite poles arebrought into corresponding excitation states in a manner facing theadjoining N and S poles, respectively, which can improve magneticbalance. As a result, whirling based on a torque ripple and the like isreduced to provide a low-vibration low-noise rotary electric machinewith an excellent performance.

Further, the slots 6 c on the outer periphery of the core 6 have beenreduced to half the number of the commutator segments 7 b. When windingthe winding wire 9 between the respective slots 6 c, because the facingdistance between the slots 6 c is reduced, the amount of the windingwire 9 (coil amount) is correspondingly reduced, copper use is reduced,and moreover, the weight is lowered thereby contributing to a reductionin size and weight. As a result, a reduction in cost is realized and, asa matter of course, commutation performance is improved. Moreover,because the respective coils 10 are wound in a so-called one-slot stridewith one slot 6 c therebetween, this structure also realizes not onlythe reduction in copper use, the reduction in size and weight, and thereduction in cost as mentioned above, but also achieves high efficiencyand the improvement in commutation performance.

Further, the coils 10 can be wound using a double flyer in a mannerstarting to wind the winding wire 9 from two points of the firstcommutator segment 7 b and eleventh commutator segment 7 b, thus afurther reduction in cost can be realized.

Here, as a matter of course, the disclosure is not limited to theembodiment described above, and can be formed as in a second embodimentshown in FIGS. 6 to 8.

The electric motor 1 according to the second embodiment is the same asthat of the first embodiment in that it is formed as an electric motorwith four poles, ten slots 6 c, and twenty commutator segments 7 b, anda pair of coils 10, that respectively conduct an electric current to thecommutator segments 7 b (riser 7 c) adjoining at both sides in thecircumferential direction with respect to an arbitrary commutatorsegment 7 b, face the poles opposite from each other. One coil 10 of thepair is wound as a normal winding, and the other, as a reverse winding.This structure is the same as the first embodiment mentioned above. Inthe second embodiment one of the coils 10 (wound in a normal windingstate) is positioned at an opposite side in the radial direction of thecommutator segment 7 b connected so as to be conductive, and the othercoil 10 (wound in a reverse winding state) is wound around in anopposite direction from the direction in which the commutator segment 7b is wound along and is wound at a position with a predetermined angleclockwise with respect to the one coil 10.

Namely, an (i-1)th coil 10 is formed by passing or connecting one end ofthe winding wire 9 around the first riser 7 c and winding the windingwire 9 around the Vth and VIIth slots 6 c with the VIth slot 6 ctherebetween a plurality of times (in the present embodiment, twentytimes) and passing the winding wire 9 around the second riser 7 c. Inthis case, the (i-1)th coil 10 is wound so as to be in a normal windingstate as a result that the winding wire 9 has been coiled from the Vthslot 6 c side to the VIIth slot 6 c. Thereafter, by winding the windingwire 9 passed around the second riser 7 c, at a section with an angle ofapproximately 90 degrees in the circumferential direction with respectto the (i-1)th coil 10, namely around the Xth slot side and the VIIIthslot 6 c with the IXth slot 6 c therebetween a plurality of times (inthe present embodiment, twenty times), and passing the winding wire 9around a third riser 7 c, an (i-2)th coil 10 in a reverse winding stateis formed.

Subsequently, a (ii-1)th coil 10 is formed by winding the winding wire 9passed around the third riser 7 c at a section from the VIth slot 6 c tothe VIIIth slot 6 c with the VIIth slot 6 c therebetween and passing thesame around a fourth riser 7 c. Then, by winding the winding wire 9passed around the fourth riser 7 c, at a section with an angle ofapproximately 90 degrees in the circumferential direction with respectto the (ii-1)th coil 10, namely around the Ist slot 6 c and the IXthslots 6 c with the Xth slot 6 c therebetween and passing the same aroundthe fifth riser 7 c, a (ii-2)th coil 10 in a reverse winding state isformed.

As such, by winding the winding wire 9 around the slots 6 c in a mannersequentially passed around the sixth, seventh, and eighth risers 7 c . .. based on the winding states, coils 10 are wound around the outerperiphery of the armature 4 in an integrated manner. And, therein aswell, similar to the first embodiment, magnetic balance can be improved,and whirling based on a torque ripple and the like is reduced, thusproviding a rotary electric machine with an excellent performance as aresult of the reduction in vibration and noise. Further, the coils 10are formed by the winding wire 9 around the commutator segments 7 b withthe slots 6 c facing in the radial direction therebetween. Therefore,interference of the winding wire 9 with other winding wire 9 can bereduced to prevent winding expansion, and a space factor of the windingwire 9 in the slots 6 c can be improved.

Also, for both armatures 4, according to the first and secondembodiments, it is also possible to carry out winding from the first andeleventh commutator segments 7 b as the start of winding by use of adouble flyer. This allows improved productivity. Here, FIGS. 8(A) and8(B) show cross-sectional views for explaining the case of winding usingthe double flyer in terms of the second embodiment, where FIG. 8(A) is across-sectional view in a state where only one of the winding wires 9has been wound, and FIG. 8(B) is a cross-sectional view in a state whereboth winding wires 9 have been wound.

Next, a third embodiment, shown in FIG. 9, will be described.

The electric motor 1 according to the third embodiment is the same asthat of the previous embodiments in that the third embodiment is formedas an electric motor with four poles, ten slots 6 c, and twentycommutator segments 7 c. Four ((2n/N)−1)) coils formed in a mannerrespectively conducting an electric current to arbitrary five ((2n/N))commutator segments 7 b adjoining in the circumferential direction arestructured as ones each of which has an angle of approximately 90degrees ((360/N)) and for which a coil 10 in a normal winding state anda coil 10 in a reverse winding state are alternately wound.

Namely, this embodiment is structured so that, in such a manner that an(i-1)th coil 10, conducting an electric current to the first and secondcommutator segments 7 b, is wound in a normal winding state around theIInd and Xth slots 6 c with the Ist slot 6 c therebetween, an (i-2)thcoil 10, conducting an electric current to the second and thirdcommutator segments 7 b, is wound in a reverse winding state around theVth and IIIrd slots 6 c with the IVth slot 6 c therebetween, an (ii-1)thcoil 10, conducting an electric current to the third and fourthcommutator segments 7 b, is wound in a normal winding state around theVIth and VIIIth slots 6 c with the VIIth slot 6 c therebetween, and an(ii-2)th coil 10, conducting an electric current to the fourth and fifthcommutator segments 7 b, is wound in a reverse winding state around theIst and IXth slots 6 c with the Xth slot 6 c therebetween, the coils 10are sequentially wound while skipping over three slots 6 c. The coils 10are wound with a predetermined gap between the adjoining coils 10, i.e.,an angle of approximately (360/N) degrees, that is, approximately(360×3/10) degrees and are wound in the sequential winding directionalternating a normal winding state with a reverse winding state.Thereby, the coils 10 connected between the brushes 8 of opposite polesare set so as to face the respective four poles provided on the innercircumference of the yoke 2 in corresponding winding directions.Consequentially, therein, magnetic balance entirely in thecircumferential direction of the armature 4 is unified, and whirlingbased on a torque ripple and the like is reduced, thus providing arotary electric machine with an excellent performance as a result of areduction in vibration and noise.

Moreover, it is also possible to form an electric motor as in a fourthembodiment shown in FIGS. 10(A), 10(B), and 11.

This embodiment is also the same as that of the previous embodiments inthat it is formed as an electric motor 1 with four poles, ten slots 6 c,and twenty commutator segments 7 c. In this fourth embodiment, coils 10are wound by use of a double flyer. For the respective coils 10, fromthe first commutator segment 7 b and eleventh commutator segment 7 b asthe start of winding, an (i-1)th coil 10 and an (vi-1)th coil 10 arerespectively wound around, by starting from the first commutator segment7 b and eleventh commutator segment 7 b, in a normal winding statebetween the VIIth and Vth slots 6 c and between the IInd and Xth slots 6c skipping over the VIth and Ist slots 6 c, respectively, facing in theradial direction. In contrast thereto, for an (i-2)th coil 10 and a(vi-2)th coil 10 subsequently formed, in a manner proceeding in anopposite direction from the direction in which the commutator segment 7b is wound along, respectively, the (i-2)th coil 10 and the (vi-2)thcoil 10 are formed in a reverse winding state around the IIIrd and Vthslots 6 c and around the Xth and VIIIth slots 6 c skipping over the IVthand IXth slots 6 c, respectively, provided with an angle ofapproximately (360/N) degrees, that is, (360×2/10) degrees relative tothe VIth and Ist slots 6 c. As such, therein, the coils 10 connected tothe adjoining commutator segments 7 b are wound with a predetermined gapof ((360×2/10) degrees, that is, approximately (360/N) degrees) fromeach other, and in a manner alternating the winding directions. Thus,the direction in which the winding wire 9 winds around the commutatorsegment 9 and the direction in which the coils 10 are wound areopposite. Accordingly, in the fourth embodiment, similar to the thirdembodiment, the coils 10 connected between the brushes 8 of oppositepoles face the respective four poles on the inner circumference of theyoke 2 in corresponding winding directions. Therefore, magnetic balanceentirely in the circumferential direction of the armature 4 is unified,and whirling based on a torque ripple and the like is reduced, thusproviding a rotary electric machine with an excellent performance as aresult of a reduction in vibration and noise. Further, in the fourthembodiment, the coils 10 are formed by winding the winding wire 9 aroundthe commutator segments 7 b with the slots 6 c facing in the radialdirection therebetween at the start of winding. Therefore, the windingwire 9 is tightly wound around the shaft 5, and a space factor of thewinding wire 9 in the slots 6 c can be improved.

A fifth embodiment, shown in FIG. 12, will now be described. The fifthembodiment is almost the same in structure as the fourth embodiment. Theelectric motor 1 is formed as an electric motor with four poles, tenslots 6 c, and twenty commutator segments 7 b. The coils 10 are wound byuse of a double flyer, which is almost the same as in the fourthembodiment. For the respective coils 10, from the first commutatorsegment 7 b and eleventh commutator segment 7 b as the start of winding,an (i-1)th coil 10 and an (vi-1)th coil 10 are wound, in a normalwinding state, between the IInd and Xth slots 6 c and between the VIIthand Vth slots 6 c, skipping over the Ist and VIth slots 6 c,respectively, facing in the axial direction with respect to the firstcommutator segment 7 b and eleventh commutator segment 7 b. Then an(i-2)th coil 10 and a (vi-2)th coil 10 are formed by moving the windingposition in an opposite direction to the previous direction in which thecommutator segments 7 b are wound. That is, the (i-2)th coil 10 and the(vi-2)th coil 10 are formed, in a reverse winding state, between theVIIIth and Xth slots 6 c and between the IIIrd and Vth slots 6 cskipping over the IXth and IVth slots 6 c, respectively, provided withan angle of approximately (360/N) degrees, that is, (360×2/10) degreesrelative to the Ist and VIth slots 6 c. As such, in the fifthembodiment, the coils 10 connected to the adjoining commutator segments7 b are wound with a predetermined gap (of (360×2/10) degrees, that is,approximately (360/N) degrees) from each other, and in a manneralternating the winding directions. Moreover, the coils 10 are wound sothat the direction in which the winding wire 9 winds around thecommutator segment 7 b and the direction in which the coils 10 are woundare opposite. Accordingly, in the fifth embodiment, similar to the thirdand fourth embodiments, the coils 10 connected between the brushes 8 ofopposite poles face the respective four poles on the inner circumferenceof the yoke 2 in corresponding winding directions, therefore, magneticbalance in the circumferential direction of the armature 4 is unified,and whirling based on a torque ripple and the like is reduced, thusproviding a low-vibration, low-noise rotary electric machine with anexcellent performance.

Furthermore, in addition to the previously described embodiments, when,for example, as the electric motor, one with four poles (N=4), ten(n=10) slots, and twenty (2n=20) commutator segments is used, it is alsopossible to provide four ((2n/N)−1) coils that respectively conduct anelectric current to the adjoining five (2n/n) commutator segments asones wound so as to face all poles (all four poles), respectively, andin this case a further improvement in magnetic balance can be expected.

Moreover, in an electric motor whose number of magnetic poles is six oreight, it is also possible to employ a structure to cause coilsconducting an electric current to adjoining commutator segments to faceadjoining opposite poles as well as a construction to cause coils toface opposite poles with a pair of magnetic poles therebetween.

Moreover, it is also possible to wind a pair of coils that respectivelyconduct an electric current to adjoining commutator segments so as tocause the same to face the same poles fixedly fitted at positionsdifferent from each other. Thus, as the electric motor, when, forexample, one with four poles (N=4), ten (n=10) slots, and twenty (2n=20)is used, a pair of coils to be wound around adjoining three commutatorsegments have an angle of approximately 180 (360×2/N) degrees so as toface poles of the same polarity with respect each other, and are woundin the same winding direction, allows provision of a rotary electricmachine excellent in magnetic balance.

A sixth embodiment, shown in FIG. 13, will be described next. Theelectric motor 1 according to the sixth embodiment is the same as thatof the previous embodiments in that it is formed as an electric motorwith four poles, ten slots 6 c, and twenty commutator segments 7 b.Furthermore, the core (armature core) 6 therein is the same in structureas the first and second embodiments. Two layers of ten coils each, atotal of twenty coils 10 are wound around the outer periphery of thecore 6. In this sixth embodiment, of these coils 10, with reference toan arbitrary slot 6 c (for example, the Ist slot in FIG. 13), where apair of coils 10 wound with the arbitrary (Ist) slot 6 c therebetweenare respectively provided as first coils 10 a and a pair of coils 10wound with (IInd or Xth) slot 6 c adjoining the arbitrary (Ist) slot 6 ctherebetween are respectively provided as second coils 10 b, these firstand second coils 10 a, 10 b are wound so as to be different in thenumber of windings of the winding wire 9 from each other. Namely, in thepresent embodiment, the coils are wound so that a ratio of the number ofwindings between the first coils 10 a and second coils 10 b is 3:1,respectively. Here, the twenty coils 10 are wound so that, as mentionedabove, the coils 10, connected between the brushes 8 of opposite poles,face at least a pair of adjoining magnetic poles in correspondingwinding directions, respectively. Therefore, magnetic balance entirelyin the circumferential direction of the armature 4 is unified, andwhirling based on a torque ripple and the like is reduced, thusproviding a low-vibration, low-noise electric motor with excellentperformance.

In the electric motor where the first and second coils 10 a, 10 b havebeen wound based on a predetermined ratio of the number of windings,commutation is improved so that the life (durability) of the brushes canbe enhanced, and noise can be reduced. Thus, an electric motor with ahigher performance can be provided.

Furthermore, in the present embodiment, the coils are wound in amutually biased state, so that the pair of first coils 10 a with agreater number of windings is located at the outer radial side, whilethe pair of second coils 10 b with a smaller number of windings islocated at the inner radial side. Thereby, in the slots 6 c, where thegroove width in the circumferential direction becomes greater toward theouter radial side, by reducing the number of windings toward the innerradial side and increasing the windings at the outer radial side by thatmuch, it becomes possible to improve the space factor of the slots 6 c.Thus, it becomes possible to realize a reduction in the radial size ofthe slots 6 c and a reduction in size and weight of the electric motor1.

Subsequently, a seventh embodiment, shown in FIG. 14, will be described.The electric motor 1 according to the seventh embodiment is the same asthat of the previously described embodiments in that this is formed asan electric motor with four poles, ten slots 6 c, and twenty commutatorsegments 7 b. Furthermore, for a core 11, teeth 11 b are formed on theouter periphery of a ring-shaped plate 11 a, which is the same as thecore 6 in the respective embodiments. The plate 11 a has a feature inthe shapes of base parts 11 d, that are components of the teeth 11 b,extend in the radial direction, so that the shapes of slots 11 c formedbetween the teeth 11 have different forms.

Namely, the base parts 11 d are each formed in a shape that is bent toone side or the other in the circumferential direction. Therefore, forthe slot 11 c formed between a pair of base parts 11 d (teeth 11 b),with reference to an arbitrary slot 11 c (for example, Ist slot 11 c inFIG. 14), the arbitrary slot (Ist slot) 11 c is formed as a first slot11 e in a shape with a small groove width at the outer radial side and agreat groove width at the inner radial side, and a (IInd or Xth) slot 11c adjoining the arbitrary (Ist) slot 11 c is formed as a second slot 11f in a shape with a small groove width at the inner radial side and agreat groove width at the outer radial side which is reverse to thefirst slot 11 e.

And, therein, when winding two layers of ten each, a total of twentycoils 10 by winding the winding wire 9 around the slots 11 c, withreference to the above-described arbitrary slot 11 c (Ist slot 11 c),where a pair of coils 10 wound with the arbitrary (Ist) slot 11 ctherebetween are respectively provided as first coils 10 a and a pair ofcoils wound with a IInd or Xth slot 11 c (second slot 11 f) adjoiningthe same therebetween are respectively provided as second coils 10 b.The pair of first coils 10 a are wound at the outer radial side with asmall groove width, and the pair of second coils 10 b, at the innerradial side with a small groove width, in a biased state, respectively,so that the winding amount of the winding wire 9 is reduced. Inaddition, when winding the first and second coils 10 a, 10 b as such,the point where the winding wire 9 is wound is to be secured as a largespace in the slots 11 c to make it possible to improve the space factorof the winding wire 9, which can contribute to a reduction in size ofthe electric motor. Moreover, in the electric motor by winding as such,not only can an overlapping part between the coils 10 be reduced incomparison with that of conventional electric motor by lap winding, butalso a crossover being the winding wire 9 between arbitrary coils 10 canbe shortened. Consequently, the amount of the winding wire 9 can bereduced to make it possible to reduce the weight. Furthermore, becausethe amount of the winding wire 9 is reduced, copper use is reduced, andhigh efficiency of the electric motor can also be realized.

Furthermore, an eighth embodiment is shown in FIGS. 15, 16(A), and16(B). The electric motor 1 according to the eighth embodiment is thesame as that of the previous embodiments in that it is formed as anelectric motor with four poles, ten slots 6 c, and twenty commutatorsegments 7 b. Further in the commutator 12 of the eight embodiment,twenty commutator segments 12 b are provided on the outer peripheralsurface of a resin-made (insulation) ring-shaped body 12 a in anintegrated manner. The respective commutator segments 12 b, have risers12 protruding therefrom to the outer radial side that are formed in anintegrated manner. The protruded front ends of the risers 12 c areformed at a side to extend away from the core 13 and formed intolatching segments 12 d that are folded back toward the inner radialside. As a result, the winding wire 9 can be easily wound around thelatching segments 12 d to connect the coils 10. Furthermore, for thecore 13, in the same manner as the seventh embodiment, a plurality ofteeth 13 b with base parts 13 d having different forms are formed on theouter periphery of a ring-shaped part 13 a. Slots 13 c, having grooveshapes of different forms, are formed between the teeth 13 b. The slots13 c adjoining in the circumferential direction are formed wherein afirst slot 13 e, with a wide groove width at the inner radial side and asecond slot 13 f, with a wide groove width at the outer radial side, areformed alternately in the circumferential direction.

When winding two layers of ten coils 10 each, for a total of twentycoils 10 on the outer periphery of the core 6, by winding the windingwire 9 around the slots 13 c, with reference to an arbitrary slot 13 c(Ist slot 13 c which is a first slot 13 e), where a pair of coils 10wound with the Ist slot 13 c therebetween are respectively provided asfirst coils 10 a and a pair of coils 10 wound with a IInd or Xth slot 13c (second slot 13 f) adjoining the same therebetween are respectivelyprovided as second coils 10 b. By winding the pair of first coils 10 aat the outer radial side with a small groove width, and the pair ofsecond coils 10 b, at the inner radial side with a small groove width,the coils 10 are wound so that the winding amount of the winding wire 9is reduced. Further, in the eighth embodiment, the coils are wound sothat a ratio of the number of winding times between the pair of firstcoils 10 a, positioned at the outer radial side, and the pair of secondcoils 10 b, positioned at the inner radial side, is 3:1, respectively.With such a structure, commutation is improved so that the life(durability) of the brushes can be enhanced, noise can be reduced, andthe space factor can be increased as in the sixth embodiment, whichallows a further reduction in the diameter of the core 13 and animprovement in performance of the electric motor 1. In addition, afurther reduction in size and weight can be realized.

Here, it is the same as in the previous embodiments that the twentycoils 10 are wound so that the coils 10 connected between the brushes 8of opposite poles face at least a pair of adjoining magnetic poles incorresponding winding directions, respectively. Therefore, magneticbalance entirely in the circumferential direction of the armature 4 isunified, and whirling based on a torque ripple and the like is reduced,thus providing a low-vibration low-noise electric motor 1 with anexcellent performance, as mentioned above.

In addition, the electric motor 1 according to a ninth embodiment, shownin FIGS. 17(A)-17(C), is the same as that of the previous embodiments inthat the ninth embodiment is formed as an electric motor with fourpoles, ten slots 6 c, and twenty commutator segments 7 b. Further thereis provided, as an insulating means of a core 14, an insulator 15 formedof an insulating resin material that is attached to the core 14.Additionally, on an inner radial side part 15 a of both axial end facesof the insulator 15, is found a plurality of integral guide pins 15 bthat extend in the axial direction arrayed in the circumferentialdirection. The guide pins 15 b, i.e., twenty guide pins 15 b, are formedaccording to the number of commutator segments 16 b of a commutator 16.Also, the commutator 16 is structured in the same manner as that of theeighth embodiment. The guide pins 15 b are positioned at the outerradial side of the latching segments 16 d which are positioned at theouter radial side of the risers 16 c, that are components of thecommutator 16. When winding the winding wire 9 around the core 14, towhich the insulator 15 has been attached, if the riser 16 c around whichthe winding wire 9 has been connected and the slot 14 to which the sameis to be drawn are distant in the circumferential direction, by drawingthe winding wire 9 so as to circumvent the outer periphery of the guidepin 15 b, interference of the winding wire 9 with the riser 16 c or thelike is avoided.

FIG. 17(A) shows a pattern view when winding the winding wire 9 by thesame process as that of the first embodiment. In this case, the (i-1)thcoil 10 (illustrated by a thin line) is created without using the guidepin 15 b because the winding wire 9 is positioned at the outer radialside relative to the risers 16 c. In the case of the (i-2)th coil 10(illustrated by a thick line), the winding wire 9 is wound around theslots with the IVth slot 14 c therebetween by drawing from the secondriser 16 c to the IIIrd slot 14 c section. Thus, the winding wire 9 isguided to the outer peripheral side using the guide pin 15 b, therebyinterference between the winding wire 9 and riser 16 c is avoided.

Thereby, a low-vibration low-noise electric motor 1 is formed by windingcoils 10 around the outer circumference of the core 14 so that the coils10 connected between the brushes of opposite poles face at least a pairof adjoining magnetic poles in corresponding winding directions,respectively, thereby unifying the magnetic balance entirely in thecircumferential direction of the armature 4. Doing so reduces whirlingbased on a torque ripple and the like, by guiding, as mentioned above,the winding wire 9 drawn along between the slot 14 c and commutator 16to the outer radial side by the guide pin 15 b. In such a case, thewinding wire 9 never interferes with the riser 16 c or latching segment16 d. Moreover, winding expansion is eliminated by drawing the samealong the guide pins 15 to achieve a reduction in size.

Also, because the commutator 16, according to the present embodiment,employs a structure that the risers 15 c are protruded to the outerdiameter side and the winding wire 9 is latched and held by the latchingsegments 15 d, the work for fusing the winding wire 9 with the riser 15c can be carried out from the direction along the axial direction. Thus,there is also an advantage in that workability can be improved.

Here, it is not always necessary to form the guide pins on theinsulator. It is sufficient that the guide pins are provided on bothaxial end portions of the slots as well as at the outer diameter siderelative to the risers. It is also possible to provide the guide pins onthe commutator side, or on a winding machine for winding winding wires.Furthermore, the guide pins may be provided only when winding windingwires and removed after winding.

In summary, the rotary electric machine according to the disclosure isuseful as a component or the like of various actuators mounted on avehicle, and is particularly suitable for use in a vehicle fan motor.

1. An armature of a rotary electric machine, the rotary electric machinecomprising: an armature on which a plurality of coils are formed bywinding a winding wire between two slots, having a predetermined numberof slots therebetween, of a plurality of slots provided side by side ina circumferential direction of the armature to conduct an electriccurrent to adjoining commutator segments; and a yoke provided withmagnetic poles, wherein the number of slots are half the number ofcommutator segments, and the coils are formed as a plurality of pairs ofcoils, each pair of coils respectively conduct an electric current tocommutator segments adjoining at both sides in the circumferentialdirection with reference to an arbitrary commutator segment, the pair ofcoils facing opposite poles positioned different from each other, onecoil of the pair of coils being wound in a normal winding state, and theother coil of the pair of coils, in a reverse winding state.
 2. Thearmature of a rotary electric machine according to claim 1, wherein therotary electric machine is formed with N magnetic poles, n slots, and 2ncommutator segments, a pair of coils that respectively conduct anelectric current to three commutator segments adjoining at both sides inthe circumferential direction with reference to an arbitrary commutatorsegment have an angle of approximately (360/N), and one coil thereof iswound as a normal winding coil, and the other coil, as a reverse windingcoil.
 3. The armature of a rotary electric machine according to claim 1,the rotary electric machine comprising N magnetic poles, n slots, and 2ncommutator segments, wherein a number (2n/N) obtained by dividing thenumber of commutator segments by the number of magnetic poles is anatural number, and ((2n/N)-1) coils formed in a manner respectivelyconducting an electric current to (2n/N) pieces of arbitrary commutatorsegments adjoining in the circumferential direction have an angle ofapproximately {(1+2m)×(360/N)} where m is a natural number including 0and are wound so that a normal winding alternates with a reversewinding.
 4. The armature of a rotary electric machine according to claim1, wherein the coils are wound with one slot therebetween.
 5. Thearmature of a rotary electric machine according to claim 1, wherein thearmature comprises two layers of coils wound in the radial direction,and with reference to an arbitrary slot, a pair of first coils in theradial direction to be wound with the arbitrary slot therebetween and apair of second coils in the radial direction to be wound with a slotadjoining the arbitrary slot therebetween are wound at a winding amountbased on a preset ratio.
 6. The armature of a rotary electric machineaccording to claim 5, wherein in the first coils and second coils, eachpair of coils are wound with a positional displacement from each otherin the radial direction.
 7. The armature of a rotary electric machineaccording to claim 1, wherein adjoining slots are formed so that agroove width of one slot is narrower at an inner diameter side and widerat an outer diameter side and a groove width of the other slot is widerat an inner diameter side and narrower at an outer diameter side.